import java.sql.*;
import javax.sql.DataSource;
import java.io.PrintWriter;
import java.util.logging.Logger;

/**
 * Database Connection Pool and ORM Examples
 * This class demonstrates the fundamental concepts of database connection pools and ORM frameworks
 */
public class DatabaseConnectionPoolAndORM {
    
    public static void main(String[] args) {
        DatabaseConnectionPoolAndORM example = new DatabaseConnectionPoolAndORM();
        
        // Demonstrating DataSource interface
        example.demonstrateDataSource();
        
        // Demonstrating connection pool concepts
        example.demonstrateConnectionPool();
        
        // Demonstrating ORM concepts
        example.demonstrateORMConcepts();
    }
    
    /**
     * Method to demonstrate DataSource interface
     */
    public void demonstrateDataSource() {
        System.out.println("=== DataSource Interface ===");
        System.out.println("DataSource is an interface that provides a way to establish database connections.");
        System.out.println("It is an alternative to DriverManager for establishing connections.");
        System.out.println("Benefits of DataSource:");
        System.out.println("1. Connection pooling capabilities");
        System.out.println("2. Distributed transactions support");
        System.out.println("3. Directory services integration");
        System.out.println("4. Better performance and scalability");
        System.out.println();
    }
    
    /**
     * Method to demonstrate connection pool concepts
     */
    public void demonstrateConnectionPool() {
        System.out.println("=== Connection Pool Concepts ===");
        System.out.println("Connection pooling is a mechanism to reuse database connections.");
        System.out.println("Instead of creating a new connection for each request, ");
        System.out.println("connections are created once and managed in a pool.");
        System.out.println();
        
        System.out.println("Common Connection Pool Implementations:");
        System.out.println("1. C3P0 - Open source JDBC connection pool");
        System.out.println("2. Druid - Alibaba's database connection pool with monitoring");
        System.out.println("3. HikariCP - High performance JDBC connection pool");
        System.out.println();
        
        // Simulate a simple connection pool
        SimpleConnectionPool pool = new SimpleConnectionPool();
        System.out.println("Created a simple connection pool simulation");
        System.out.println("Pool initial size: " + pool.getPoolSize());
        System.out.println();
    }
    
    /**
     * Method to demonstrate ORM concepts
     */
    public void demonstrateORMConcepts() {
        System.out.println("=== ORM Framework Concepts ===");
        System.out.println("Object-Relational Mapping (ORM) is a technique that");
        System.out.println("maps objects in an object-oriented programming language");
        System.out.println("to tables in a relational database.");
        System.out.println();
        
        System.out.println("Popular ORM Frameworks:");
        System.out.println("1. MyBatis - SQL mapping framework");
        System.out.println("2. Hibernate - Full ORM solution");
        System.out.println("3. JPA - Java Persistence API specification");
        System.out.println();
        
        // Simulate ORM usage
        simulateORMUsage();
    }
    
    /**
     * Method to simulate ORM usage
     */
    public void simulateORMUsage() {
        System.out.println("Simulating ORM usage:");
        
        // Create a sample entity
        User user = new User();
        user.setId(1);
        user.setName("John Doe");
        user.setEmail("john.doe@example.com");
        
        System.out.println("Created User object:");
        System.out.println("ID: " + user.getId());
        System.out.println("Name: " + user.getName());
        System.out.println("Email: " + user.getEmail());
        System.out.println();
        
        System.out.println("In a real ORM framework like Hibernate or MyBatis:");
        System.out.println("1. The User object would be mapped to a 'users' table");
        System.out.println("2. Object properties would map to table columns");
        System.out.println("3. Operations on the object would generate SQL queries");
        System.out.println("4. Results would be automatically mapped back to objects");
        System.out.println();
    }
}

/**
 * Simple Connection Pool Simulation
 */
class SimpleConnectionPool {
    private int poolSize = 10;
    
    public SimpleConnectionPool() {
        // Simulate pool initialization
        initializePool();
    }
    
    private void initializePool() {
        System.out.println("Initializing connection pool with " + poolSize + " connections");
        // In a real implementation, this would create actual database connections
    }
    
    public int getPoolSize() {
        return poolSize;
    }
    
    // Simulate getting a connection from the pool
    public Connection getConnection() {
        System.out.println("Getting connection from pool");
        // In a real implementation, this would return an actual database connection
        return null;
    }
    
    // Simulate returning a connection to the pool
    public void returnConnection(Connection conn) {
        System.out.println("Returning connection to pool");
        // In a real implementation, this would return the connection to the pool
    }
}

/**
 * Sample User Entity for ORM demonstration
 */
class User {
    private int id;
    private String name;
    private String email;
    
    // Constructors
    public User() {
    }
    
    public User(int id, String name, String email) {
        this.id = id;
        this.name = name;
        this.email = email;
    }
    
    // Getters and Setters
    public int getId() {
        return id;
    }
    
    public void setId(int id) {
        this.id = id;
    }
    
    public String getName() {
        return name;
    }
    
    public void setName(String name) {
        this.name = name;
    }
    
    public String getEmail() {
        return email;
    }
    
    public void setEmail(String email) {
        this.email = email;
    }
    
    @Override
    public String toString() {
        return "User{id=" + id + ", name='" + name + "', email='" + email + "'}";
    }
}

/**
 * Simple DataSource implementation simulation
 */
class SimpleDataSource implements DataSource {
    private String url;
    private String username;
    private String password;
    
    public SimpleDataSource() {
    }
    
    public SimpleDataSource(String url, String username, String password) {
        this.url = url;
        this.username = username;
        this.password = password;
    }
    
    @Override
    public Connection getConnection() throws SQLException {
        System.out.println("Creating connection to: " + url);
        System.out.println("Username: " + username);
        // In a real implementation, this would create an actual database connection
        return null;
    }
    
    @Override
    public Connection getConnection(String username, String password) throws SQLException {
        System.out.println("Creating connection with provided credentials");
        // In a real implementation, this would create an actual database connection
        return null;
    }
    
    // Other DataSource methods - implemented as needed
    @Override
    public PrintWriter getLogWriter() throws SQLException {
        return null;
    }
    
    @Override
    public void setLogWriter(PrintWriter out) throws SQLException {
    }
    
    @Override
    public void setLoginTimeout(int seconds) throws SQLException {
    }
    
    @Override
    public int getLoginTimeout() throws SQLException {
        return 0;
    }
    
    @Override
    public Logger getParentLogger() throws SQLFeatureNotSupportedException {
        return null;
    }
    
    @Override
    public <T> T unwrap(Class<T> iface) throws SQLException {
        return null;
    }
    
    @Override
    public boolean isWrapperFor(Class<?> iface) throws SQLException {
        return false;
    }
    
    // Getters and setters for properties
    public String getUrl() {
        return url;
    }
    
    public void setUrl(String url) {
        this.url = url;
    }
    
    public String getUsername() {
        return username;
    }
    
    public void setUsername(String username) {
        this.username = username;
    }
    
    public String getPassword() {
        return password;
    }
    
    public void setPassword(String password) {
        this.password = password;
    }
}